Using the error diffusion method to print documents through a medium resolution (typically between 300 dpi and 600 dpi) printer has three drawbacks: (1) the snake-like noise disturbs the white background; (2) the printed image is too dark to distinguish the details; (3) the printed text exhibits a coarse edge. In this paper, the authors propose some methods to overcome these shortcomings. In order to eliminate the first shortcoming, a white minimum threshold value is set to calibrate the diffused errors. For the second shortcoming, a tone-scale adjustment function is used to lighten the images. Finally, an edge enhancement algorithm is introduced to overcome the third shortcoming.